Pamela S. Jensen

Early radiographic manifestations of secondary hyperparathyroidism associated with chronic renal disease.

The hands of 29 chronic dialysis patients were evaluated every 3 months for subperiosteal, intracortical, and endosteal bone resorption using fine-detail radiography and optical magnification. All patients with significant endosteal resorption also had progressive subperiosteal resorption and substantial or progressive intracortical resorption. All patients with a significantly elevated parathyroid hormone or alkaline phosphatase level had radiographic evidence of progressive bone loss. Fourteen (61%) of the 23 patients with well-controlled serum phosphate levels (mean 4.7 +/- 0.2 mg/dl) treated with supplemental calcium and dihydrotachysterol nevertheless had increased subperiosteal or endosteal resorption. Serial radiography proved to be a valuable method of evaluating progressive bone resorption.

Radiology of Postnatal Skeletal development: The proximal humerus

Twenty-three pairs of proximal humeri obtained from human cadavers ranging in age from fullterm stillborn to fourteen years were studied morphologically and radiographically. Roentgenograms of the specimens demonstrated the osseous and cartilaginous portions of the epiphyses, using air/cartilage interfacing. Comparable clinical simulations were obtained by using water immersion of the specimens. The metaphyseal cortex remained thin and trabecular near the physis. Histologically this area had multiple fenestrations, which provide a potential pathway for childhood osteomyelitis into the subperiosteal space, and may also affect the biomechanics of this region (i.e., susceptibility to Salter epiphyseal fractures). As skeletal maturity was reached, thicker cortical (osteonal) bone extended toward the physis. The epiphyseal secondary ossification centers form an osseous connection shortly after the appearance of greater tuberosity ossification center, although this may not be radiologically evident until the child is older. The major intent of this roentgenographic survey is to provide a reference index of proximal humeral development for the adequate interpretation of shoulder radiography in children who have not yet attained skeletal maturity.

Bone Mineral Analysis Using Single-Energy Computed Tomography

We present a new method for evaluating in vivo changes in bone mineralization in the peripheral skeleton, using computed tomography (CT). A set of bone mineralization indices are generated from numerous CT images of the patients distal radius. The cross-sectional anatomy displayed by the CT scan allows for separate evaluation of the cortical and trabecular bone. Correction for possible drift of the CT number scale (Hounsfield scale) is achieved by scanning standard solutions of dipotassium hydrogen phosphate simultaneously with the forearm. Preliminary data indicate that this is a precise method for evaluating in vivo changes in bone mineralization.

Chondrocalcinosis and haemophilia

Chondrocalcinosis has been found in a wide variety of diseases. Cartilage calcification is commonly noted in patients with haemochromatosis, but it has not been previously reported in haemophilia, although increased levels of iron are present in the joints in both these conditions. The radiographic demonstration of chondrocalcinosis in patients with advanced joint changes due to haemophilia is precluded by the extensive joint narrowing and cartilage damage associated with the repeated haemarthroses. Cartilage calcification in less severely damaged joints of three patients with Factor VII, AHG-deficient haemophilia is described. Inhibition of pyrophosphatase activity by divalent cations as a cause of calcium pyrophosphate dihydrate (CPPD) deposition in cartilage is reviewed. The biomechanics of articular cartilage and the effects of divalent cations on normal cartilage elasticity are discussed. The possibility that both the development of the degenerative joint changes and the associated chondrocalcinosis may occur simultaneously due to the presence of abnormal divalent cations is suggested.

Roentgenography of Congenital Dislocation of the Hip

The chronically dislocated hip of a 15-month-old girl was studied postmortem. The cartilaginous components of the pelvis (both true and false acetabula) and proximal femur were demonstrated roentgenographically and correlated with gross anatomical observations. These findings should be useful in the interpretation of radiographs in congenital hip dysplasia in children.

Science, Technology and Medicine

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EFFECT OF THE IONOPHORE A23187 UPON LYMPHOCYTE CALCIUM METABOLISM

Publisher Summary This chapter explores the effect of the ionophore A23187 upon lymphocyte calcium metabolism. The ionophore A23187 has been shown to induce lymphocyte proliferation in a calcium dependent manner, thus, lending support to the hypothesis that calcium is a critical intracellular signal in the initiation of lymphocyte transformation. A study described in the chapter investigated the effect of A23187 on human lymphocyte calcium metabolism in an effort to correlate changes in cellular calcium with initiation of transformation. Freshly isolated human peripheral lymphocytes suspended in MEM plus 10% AB serum were used in all experiments described in the chapter. Using the techniques of atomic absorption spectroscopy and 45 Ca uptake, it was determined that the mitogenic concentrations of A23187 result in a net increase in calcium content of human lymphocytes. However, the increased calcium was not retained, and over a period of many hours, the calcium content of A23187-treated lymphocytes declined to levels approaching control values. As the respiratory uncoupler FCCP was capable of blocking at least 95% of the A23187-induced 45 Ca uptake, it was concluded that most of the calcium accumulated in ionophore-treated lymphocytes was sequestered by the mitochondria.